// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */

#include <test_progs.h>
#include <bpf/btf.h>

#include "test_log_buf.skel.h"


static bool check_prog_load(int prog_fd, bool expect_err, const char *tag)
{
        if (expect_err) {
                if (!ASSERT_LT(prog_fd, 0, tag)) {
                        close(prog_fd);
                        return false;
                }
        } else /* !expect_err */ {
                if (!ASSERT_GT(prog_fd, 0, tag))
                        return false;
        }
        if (prog_fd >= 0)
                close(prog_fd);
        return true;
}

static struct {
        /* strategically placed before others to avoid accidental modification by kernel */
        char filler[1024];
        char buf[1024];
        /* strategically placed after buf[] to catch more accidental corruptions */
        char reference[1024];
} logs;
static const struct bpf_insn *insns;
static size_t insn_cnt;

static int load_prog(struct bpf_prog_load_opts *opts, bool expect_load_error)
{
        int prog_fd;

        prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_prog",
                                "GPL", insns, insn_cnt, opts);
        check_prog_load(prog_fd, expect_load_error, "prog_load");

        return prog_fd;
}

static void verif_log_subtest(const char *name, bool expect_load_error, int log_level)
{
        LIBBPF_OPTS(bpf_prog_load_opts, opts);
        char *exp_log, prog_name[24], op_name[32];
        struct test_log_buf *skel;
        struct bpf_program *prog;
        size_t fixed_log_sz;
        __u32 log_true_sz_fixed, log_true_sz_rolling;
        int i, mode, err, prog_fd, res;

        skel = test_log_buf__open();
        if (!ASSERT_OK_PTR(skel, "skel_open"))
                return;

        bpf_object__for_each_program(prog, skel->obj) {
                if (strcmp(bpf_program__name(prog), name) == 0)
                        bpf_program__set_autoload(prog, true);
                else
                        bpf_program__set_autoload(prog, false);
        }

        err = test_log_buf__load(skel);
        if (!expect_load_error && !ASSERT_OK(err, "unexpected_load_failure"))
                goto cleanup;
        if (expect_load_error && !ASSERT_ERR(err, "unexpected_load_success"))
                goto cleanup;

        insns = bpf_program__insns(skel->progs.good_prog);
        insn_cnt = bpf_program__insn_cnt(skel->progs.good_prog);

        opts.log_buf = logs.reference;
        opts.log_size = sizeof(logs.reference);
        opts.log_level = log_level | 8 /* BPF_LOG_FIXED */;
        load_prog(&opts, expect_load_error);

        fixed_log_sz = strlen(logs.reference) + 1;
        if (!ASSERT_GT(fixed_log_sz, 50, "fixed_log_sz"))
                goto cleanup;
        memset(logs.reference + fixed_log_sz, 0, sizeof(logs.reference) - fixed_log_sz);

        /* validate BPF_LOG_FIXED works as verifier log used to work, that is:
         * we get -ENOSPC and beginning of the full verifier log. This only
         * works for log_level 2 and log_level 1 + failed program. For log
         * level 2 we don't reset log at all. For log_level 1 + failed program
         * we don't get to verification stats output. With log level 1
         * for successful program  final result will be just verifier stats.
         * But if provided too short log buf, kernel will NULL-out log->ubuf
         * and will stop emitting further log. This means we'll never see
         * predictable verifier stats.
         * Long story short, we do the following -ENOSPC test only for
         * predictable combinations.
         */
        if (log_level >= 2 || expect_load_error) {
                opts.log_buf = logs.buf;
                opts.log_level = log_level | 8; /* fixed-length log */
                opts.log_size = 25;

                prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_fixed25",
                                        "GPL", insns, insn_cnt, &opts);
                if (!ASSERT_EQ(prog_fd, -ENOSPC, "unexpected_log_fixed_prog_load_result")) {
                        if (prog_fd >= 0)
                                close(prog_fd);
                        goto cleanup;
                }
                if (!ASSERT_EQ(strlen(logs.buf), 24, "log_fixed_25"))
                        goto cleanup;
                if (!ASSERT_STRNEQ(logs.buf, logs.reference, 24, "log_fixed_contents_25"))
                        goto cleanup;
        }

        /* validate rolling verifier log logic: try all variations of log buf
         * length to force various truncation scenarios
         */
        opts.log_buf = logs.buf;

        /* rotating mode, then fixed mode */
        for (mode = 1; mode >= 0; mode--) {
                /* prefill logs.buf with 'A's to detect any write beyond allowed length */
                memset(logs.filler, 'A', sizeof(logs.filler));
                logs.filler[sizeof(logs.filler) - 1] = '\0';
                memset(logs.buf, 'A', sizeof(logs.buf));
                logs.buf[sizeof(logs.buf) - 1] = '\0';

                for (i = 1; i < fixed_log_sz; i++) {
                        opts.log_size = i;
                        opts.log_level = log_level | (mode ? 0 : 8 /* BPF_LOG_FIXED */);

                        snprintf(prog_name, sizeof(prog_name),
                                 "log_%s_%d", mode ? "roll" : "fixed", i);
                        prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, prog_name,
                                                "GPL", insns, insn_cnt, &opts);

                        snprintf(op_name, sizeof(op_name),
                                 "log_%s_prog_load_%d", mode ? "roll" : "fixed", i);
                        if (!ASSERT_EQ(prog_fd, -ENOSPC, op_name)) {
                                if (prog_fd >= 0)
                                        close(prog_fd);
                                goto cleanup;
                        }

                        snprintf(op_name, sizeof(op_name),
                                 "log_%s_strlen_%d", mode ? "roll" : "fixed", i);
                        ASSERT_EQ(strlen(logs.buf), i - 1, op_name);

                        if (mode)
                                exp_log = logs.reference + fixed_log_sz - i;
                        else
                                exp_log = logs.reference;

                        snprintf(op_name, sizeof(op_name),
                                 "log_%s_contents_%d", mode ? "roll" : "fixed", i);
                        if (!ASSERT_STRNEQ(logs.buf, exp_log, i - 1, op_name)) {
                                printf("CMP:%d\nS1:'%s'\nS2:'%s'\n",
                                        strncmp(logs.buf, exp_log, i - 1),
                                        logs.buf, exp_log);
                                goto cleanup;
                        }

                        /* check that unused portions of logs.buf is not overwritten */
                        snprintf(op_name, sizeof(op_name),
                                 "log_%s_unused_%d", mode ? "roll" : "fixed", i);
                        if (!ASSERT_STREQ(logs.buf + i, logs.filler + i, op_name)) {
                                printf("CMP:%d\nS1:'%s'\nS2:'%s'\n",
                                        strcmp(logs.buf + i, logs.filler + i),
                                        logs.buf + i, logs.filler + i);
                                goto cleanup;
                        }
                }
        }

        /* (FIXED) get actual log size */
        opts.log_buf = logs.buf;
        opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
        opts.log_size = sizeof(logs.buf);
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_fixed");

        log_true_sz_fixed = opts.log_true_size;
        ASSERT_GT(log_true_sz_fixed, 0, "log_true_sz_fixed");

        /* (FIXED, NULL) get actual log size */
        opts.log_buf = NULL;
        opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
        opts.log_size = 0;
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_fixed_null");
        ASSERT_EQ(opts.log_true_size, log_true_sz_fixed, "log_sz_fixed_null_eq");

        /* (ROLLING) get actual log size */
        opts.log_buf = logs.buf;
        opts.log_level = log_level;
        opts.log_size = sizeof(logs.buf);
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_rolling");

        log_true_sz_rolling = opts.log_true_size;
        ASSERT_EQ(log_true_sz_rolling, log_true_sz_fixed, "log_true_sz_eq");

        /* (ROLLING, NULL) get actual log size */
        opts.log_buf = NULL;
        opts.log_level = log_level;
        opts.log_size = 0;
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_rolling_null");
        ASSERT_EQ(opts.log_true_size, log_true_sz_rolling, "log_true_sz_null_eq");

        /* (FIXED) expect -ENOSPC for one byte short log */
        opts.log_buf = logs.buf;
        opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
        opts.log_size = log_true_sz_fixed - 1;
        opts.log_true_size = 0;
        res = load_prog(&opts, true /* should fail */);
        ASSERT_EQ(res, -ENOSPC, "prog_load_res_too_short_fixed");

        /* (FIXED) expect *not* -ENOSPC with exact log_true_size buffer */
        opts.log_buf = logs.buf;
        opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
        opts.log_size = log_true_sz_fixed;
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_just_right_fixed");

        /* (ROLLING) expect -ENOSPC for one byte short log */
        opts.log_buf = logs.buf;
        opts.log_level = log_level;
        opts.log_size = log_true_sz_rolling - 1;
        res = load_prog(&opts, true /* should fail */);
        ASSERT_EQ(res, -ENOSPC, "prog_load_res_too_short_rolling");

        /* (ROLLING) expect *not* -ENOSPC with exact log_true_size buffer */
        opts.log_buf = logs.buf;
        opts.log_level = log_level;
        opts.log_size = log_true_sz_rolling;
        opts.log_true_size = 0;
        res = load_prog(&opts, expect_load_error);
        ASSERT_NEQ(res, -ENOSPC, "prog_load_res_just_right_rolling");

cleanup:
        test_log_buf__destroy(skel);
}

static const void *btf_data;
static u32 btf_data_sz;

static int load_btf(struct bpf_btf_load_opts *opts, bool expect_err)
{
        int fd;

        fd = bpf_btf_load(btf_data, btf_data_sz, opts);
        if (fd >= 0)
                close(fd);
        if (expect_err)
                ASSERT_LT(fd, 0, "btf_load_failure");
        else /* !expect_err */
                ASSERT_GT(fd, 0, "btf_load_success");
        return fd;
}

static void verif_btf_log_subtest(bool bad_btf)
{
        LIBBPF_OPTS(bpf_btf_load_opts, opts);
        struct btf *btf;
        struct btf_type *t;
        char *exp_log, op_name[32];
        size_t fixed_log_sz;
        __u32 log_true_sz_fixed, log_true_sz_rolling;
        int i, res;

        /* prepare simple BTF contents */
        btf = btf__new_empty();
        if (!ASSERT_OK_PTR(btf, "btf_new_empty"))
                return;
        res = btf__add_int(btf, "whatever", 4, 0);
        if (!ASSERT_GT(res, 0, "btf_add_int_id"))
                goto cleanup;
        if (bad_btf) {
                /* btf__add_int() doesn't allow bad value of size, so we'll just
                 * force-cast btf_type pointer and manually override size to invalid
                 * 3 if we need to simulate failure
                 */
                t = (void *)btf__type_by_id(btf, res);
                if (!ASSERT_OK_PTR(t, "int_btf_type"))
                        goto cleanup;
                t->size = 3;
        }

        btf_data = btf__raw_data(btf, &btf_data_sz);
        if (!ASSERT_OK_PTR(btf_data, "btf_data"))
                goto cleanup;

        load_btf(&opts, bad_btf);

        opts.log_buf = logs.reference;
        opts.log_size = sizeof(logs.reference);
        opts.log_level = 1 | 8 /* BPF_LOG_FIXED */;
        load_btf(&opts, bad_btf);

        fixed_log_sz = strlen(logs.reference) + 1;
        if (!ASSERT_GT(fixed_log_sz, 50, "fixed_log_sz"))
                goto cleanup;
        memset(logs.reference + fixed_log_sz, 0, sizeof(logs.reference) - fixed_log_sz);

        /* validate BPF_LOG_FIXED truncation works as verifier log used to work */
        opts.log_buf = logs.buf;
        opts.log_level = 1 | 8; /* fixed-length log */
        opts.log_size = 25;
        res = load_btf(&opts, true);
        ASSERT_EQ(res, -ENOSPC, "half_log_fd");
        ASSERT_EQ(strlen(logs.buf), 24, "log_fixed_25");
        ASSERT_STRNEQ(logs.buf, logs.reference, 24, op_name);

        /* validate rolling verifier log logic: try all variations of log buf
         * length to force various truncation scenarios
         */
        opts.log_buf = logs.buf;
        opts.log_level = 1; /* rolling log */

        /* prefill logs.buf with 'A's to detect any write beyond allowed length */
        memset(logs.filler, 'A', sizeof(logs.filler));
        logs.filler[sizeof(logs.filler) - 1] = '\0';
        memset(logs.buf, 'A', sizeof(logs.buf));
        logs.buf[sizeof(logs.buf) - 1] = '\0';

        for (i = 1; i < fixed_log_sz; i++) {
                opts.log_size = i;

                snprintf(op_name, sizeof(op_name), "log_roll_btf_load_%d", i);
                res = load_btf(&opts, true);
                if (!ASSERT_EQ(res, -ENOSPC, op_name))
                        goto cleanup;

                exp_log = logs.reference + fixed_log_sz - i;
                snprintf(op_name, sizeof(op_name), "log_roll_contents_%d", i);
                if (!ASSERT_STREQ(logs.buf, exp_log, op_name)) {
                        printf("CMP:%d\nS1:'%s'\nS2:'%s'\n",
                                strcmp(logs.buf, exp_log),
                                logs.buf, exp_log);
                        goto cleanup;
                }

                /* check that unused portions of logs.buf are not overwritten */
                snprintf(op_name, sizeof(op_name), "log_roll_unused_tail_%d", i);
                if (!ASSERT_STREQ(logs.buf + i, logs.filler + i, op_name)) {
                        printf("CMP:%d\nS1:'%s'\nS2:'%s'\n",
                                strcmp(logs.buf + i, logs.filler + i),
                                logs.buf + i, logs.filler + i);
                        goto cleanup;
                }
        }

        /* (FIXED) get actual log size */
        opts.log_buf = logs.buf;
        opts.log_level = 1 | 8; /* BPF_LOG_FIXED */
        opts.log_size = sizeof(logs.buf);
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_fixed");

        log_true_sz_fixed = opts.log_true_size;
        ASSERT_GT(log_true_sz_fixed, 0, "log_true_sz_fixed");

        /* (FIXED, NULL) get actual log size */
        opts.log_buf = NULL;
        opts.log_level = 1 | 8; /* BPF_LOG_FIXED */
        opts.log_size = 0;
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_fixed_null");
        ASSERT_EQ(opts.log_true_size, log_true_sz_fixed, "log_sz_fixed_null_eq");

        /* (ROLLING) get actual log size */
        opts.log_buf = logs.buf;
        opts.log_level = 1;
        opts.log_size = sizeof(logs.buf);
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_rolling");

        log_true_sz_rolling = opts.log_true_size;
        ASSERT_EQ(log_true_sz_rolling, log_true_sz_fixed, "log_true_sz_eq");

        /* (ROLLING, NULL) get actual log size */
        opts.log_buf = NULL;
        opts.log_level = 1;
        opts.log_size = 0;
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_rolling_null");
        ASSERT_EQ(opts.log_true_size, log_true_sz_rolling, "log_true_sz_null_eq");

        /* (FIXED) expect -ENOSPC for one byte short log */
        opts.log_buf = logs.buf;
        opts.log_level = 1 | 8; /* BPF_LOG_FIXED */
        opts.log_size = log_true_sz_fixed - 1;
        opts.log_true_size = 0;
        res = load_btf(&opts, true);
        ASSERT_EQ(res, -ENOSPC, "btf_load_res_too_short_fixed");

        /* (FIXED) expect *not* -ENOSPC with exact log_true_size buffer */
        opts.log_buf = logs.buf;
        opts.log_level = 1 | 8; /* BPF_LOG_FIXED */
        opts.log_size = log_true_sz_fixed;
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_just_right_fixed");

        /* (ROLLING) expect -ENOSPC for one byte short log */
        opts.log_buf = logs.buf;
        opts.log_level = 1;
        opts.log_size = log_true_sz_rolling - 1;
        res = load_btf(&opts, true);
        ASSERT_EQ(res, -ENOSPC, "btf_load_res_too_short_rolling");

        /* (ROLLING) expect *not* -ENOSPC with exact log_true_size buffer */
        opts.log_buf = logs.buf;
        opts.log_level = 1;
        opts.log_size = log_true_sz_rolling;
        opts.log_true_size = 0;
        res = load_btf(&opts, bad_btf);
        ASSERT_NEQ(res, -ENOSPC, "btf_load_res_just_right_rolling");

cleanup:
        btf__free(btf);
}

void test_verifier_log(void)
{
        if (test__start_subtest("good_prog-level1"))
                verif_log_subtest("good_prog", false, 1);
        if (test__start_subtest("good_prog-level2"))
                verif_log_subtest("good_prog", false, 2);
        if (test__start_subtest("bad_prog-level1"))
                verif_log_subtest("bad_prog", true, 1);
        if (test__start_subtest("bad_prog-level2"))
                verif_log_subtest("bad_prog", true, 2);
        if (test__start_subtest("bad_btf"))
                verif_btf_log_subtest(true /* bad btf */);
        if (test__start_subtest("good_btf"))
                verif_btf_log_subtest(false /* !bad btf */);
}